Glioma microvesicles are abundantly shed into circulation, can be detected in the majority of clinical patients and are being explored as biomarkers for therapy assessment. A current major challenge and opportunity is the ability to develop methods for rapidly determining the abundance and composition of microvesicles from clinical samples. We have recently developed a novel, highly sensitive, nanotechnology based, point-of-care diagnostic method termed DMR (diagnostic magnetic resonance). The molecular specificity of DMR is achieved through magnetic nanoparticles that act as sensors for specific molecular targets. In preliminary feasibility experiments, we have profiled intact cancer cells in a prospective clinical trial (Science TransI Med 2011, in press) and also shown that we can sensitively detected and profile (via CD63, EGFR, EGFRv3, PDGFR, podoplanin, EphA2, CD41, MHCII) microvesicles in plasma samples. The overall goal of this revised proposal is to further advance the DMR technology and to apply it to more comprehensive profiling of microvesicles in glioma patients undergoing treatment. In aim 1 we will develop, calibrate and validate DMR for measuring microvesicle concentration and protein markers of interest (EGFRvlll, EGFR/pEGFR, S6 ribosomal protein/pSSrp, CD63, Gag polyprotein pr65, CYR61) in cells and novel mouse models. In aim 2 we will develop a new microfluidic chip that integrates filters, mixing chambers and micro-NMR components to separate microvesicles from whole blood and directly detect them in one step. Finally, in aim 3 we will study clinical samples in an effort to predict therapeutic efficacy in individual patients undergoing glioma treatment. Patient samples originate from two different sources: 1) an ongoing multi-institutional clinical trial in glioma patients undergoing standard-of-care, and 2) a prospective clinical trial evaluating new glioma therapy approaches. This project is highly interactive with Project 3 (Drs. Breakefield/Skog) and Project 1 (Drs. Chiocca/Kaur). The Biorepository Core (Core B; Dr. Carter) will supply samples from clinical trials and the Mouse Models Core (Dr. Charest) will provide mouse models for preclinical testing. We ultimately envision using this technology in a point-of-care setting to quantitate both exosome number and composition, which could serve as a rapid measure of therapeutic efficacy in clinical trials.